Using conventional techniques, a silicon chip may be connected to a chip carrier via a flip chip process which utilizes small solder balls, also known as controlled collapse chip connections (C4s). The chip may then be attached to its carrier by a standard solder joining process, or an alternative attachment means. The chip carrier then directs the chip signals and power connections of the silicon chip to bottom side carrier pads. Several technologies have been used to attach the C4 solder balls to a chip, for example, by evaporation or by electroplating metal onto the pads of the chip. Recently, a process known as controlled collapse chip connection new process (C4NP) has been proposed. C4NP directly deposits solder onto a pad by contact transfer. The deposited solder forms C4 solder balls via a thermal reflow process.
C4NP technology has the potential to revolutionize the wafer bumping industry by enabling the bumping of many leaded and lead-free solders in a speedy and cost effective manner. For example, the C4NP process facilitates mass production of solder deposits. This is accomplished by filling cavities in a glass mold plate with molten solder. Naturally, as the molten solder is dispensed, it oxidizes rapidly as it is exposed to air. Solder, which usually consists of tin, becomes extremely hard and abrasive when it is oxidized. In many instances, the oxidized solder builds up on a fill head seal of the solder dispenser. This buildup degrades the life of the fill head seal and further results in unwanted solder residue on the glass mold plate.